I will tell you.
I'm who had experienced with a lot of antivirus.
Paid vs Free who is the best?
Of course, you shouldn't think about it, is PAID. Because of release of new version and update of new databases and improving the product, which the free can lack in this part.
Also some modules like Machine Learning some of this are only available in paid version, firewall which is very important and HIPS.
Here is my TOP Best Antivirus PAID.
1. Kaspersky / BitDefender - Both are Strong enough, however Kaspersky is more complete and with more features you won't find in BitDefender, but BitDefender still have a good detection. Malware Remediation of Kaspersky (called Rollback) is very good.
2. ESET - Do you want a good antivirus, and using less CPU and RAM? ESET is very very light in your computer, you won't notice. They are good in updating about new malware, specially 0day malware they are very fast in adding it to their database, also they are very stable product, definitely a good choice.
3. Emsisoft / GData - Both are great, not better than TOP 2 and 3, but does their job. Trust me, Emsisoft is very good product also they did decrypters for FREE! Yes for free, to a millions of people recovered their computer, thanks to Emsisoft! Emsisoft have solid and good products, you will be also safe. GData have a good anti-malware dectetion with their new BEAST Technology.
Don't use McAffee, Avast, AVG and Windows Defender they can be bypassed easily (and yes kaspersky also can, but they are more harder than others).
For who have childrens, and sharing your computer with Family, definetly a Paid Antivirus is a MUST, in my opinion. Otherwise you can lose documents, files, docs, photos and be hacked because of your childrens or family that are using that and installing everything without knowing that can be malware / PUP / adware which can lead to spyware and probably you being hacked.